A telescope composed of an objective lens forming an image of an object disposed at infinity and an eyepiece for enlarging the image of the object formed by the objective lens has been generally known (for example, see Japanese Examined Patent Application Publication No. 6-14131).
However, a telescope capable of observing an image of an object formed by a single objective lens with two eyepiece optical systems, in other word, binocular observation has not been proposed. Accordingly, a telescope capable of performing binocular observation by introducing binocular optical system into a conventional telescope can be considered, though the focal length of the objective lens is necessary to be short in order to shorten the total length of the telescope. However, when the focal length of the objective lens is made short, a distance between the objective lens and an image formed by the objective lens becomes short, so that it becomes difficult to secure a space for introducing the binocular optical system.